EP0928984B1 - Optische Kompensationsfolie und Flüssigkristallanzeige - Google Patents

Optische Kompensationsfolie und Flüssigkristallanzeige Download PDF

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EP0928984B1
EP0928984B1 EP99100130A EP99100130A EP0928984B1 EP 0928984 B1 EP0928984 B1 EP 0928984B1 EP 99100130 A EP99100130 A EP 99100130A EP 99100130 A EP99100130 A EP 99100130A EP 0928984 B1 EP0928984 B1 EP 0928984B1
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Prior art keywords
liquid crystal
group
optical compensatory
discotic
crystal molecules
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EP99100130A
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French (fr)
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EP0928984B8 (de
EP0928984A2 (de
EP0928984A3 (de
Inventor
Shigeki Yokohama
Ken Kawata
Hideyuki Nishikawa
Koshin Matsuoka
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Fujifilm Holdings Corp
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Fuji Photo Film Co Ltd
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    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
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    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/32—Non-steroidal liquid crystal compounds containing condensed ring systems, i.e. fused, bridged or spiro ring systems
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    • C09K19/00—Liquid crystal materials
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    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
    • C09K19/30—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing saturated or unsaturated non-aromatic rings, e.g. cyclohexane rings
    • C09K19/3001—Cyclohexane rings
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    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/34—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring
    • C09K19/3441—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring having nitrogen as hetero atom
    • C09K19/3475—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring having nitrogen as hetero atom the heterocyclic ring being a six-membered aromatic ring containing at least three nitrogen atoms
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    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/34—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring
    • C09K19/3441—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring having nitrogen as hetero atom
    • C09K19/3477—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring having nitrogen as hetero atom the heterocyclic ring being a five-membered aromatic ring containing at least one nitrogen atom
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    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/34—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring
    • C09K19/3441—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring having nitrogen as hetero atom
    • C09K19/3488—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring having nitrogen as hetero atom the heterocyclic ring having more than 6 members, e.g. macrocycles, phthalocyanines
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    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/34—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring
    • C09K19/3491—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring having sulfur as hetero atom
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    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/38—Polymers
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    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/40—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit containing elements other than carbon, hydrogen, halogen, oxygen, nitrogen or sulfur, e.g. silicon, metals
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3016—Polarising elements involving passive liquid crystal elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/13363—Birefringent elements, e.g. for optical compensation
    • G02F1/133632—Birefringent elements, e.g. for optical compensation with refractive index ellipsoid inclined relative to the LC-layer surface
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/13363—Birefringent elements, e.g. for optical compensation
    • G02F1/133634—Birefringent elements, e.g. for optical compensation the refractive index Nz perpendicular to the element surface being different from in-plane refractive indices Nx and Ny, e.g. biaxial or with normal optical axis
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/137—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
    • G02F1/139—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering based on orientation effects in which the liquid crystal remains transparent
    • G02F1/1393—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering based on orientation effects in which the liquid crystal remains transparent the birefringence of the liquid crystal being electrically controlled, e.g. ECB-, DAP-, HAN-, PI-LC cells
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/06—Non-steroidal liquid crystal compounds
    • C09K19/34—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring
    • C09K19/3402—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring having oxygen as hetero atom
    • C09K19/3405—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring having oxygen as hetero atom the heterocyclic ring being a five-membered ring
    • C09K2019/3408—Five-membered ring with oxygen(s) in fused, bridged or spiro ring systems
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2413/00—Indexing scheme related to G02F1/13363, i.e. to birefringent elements, e.g. for optical compensation, characterised by the number, position, orientation or value of the compensation plates
    • G02F2413/10—Indexing scheme related to G02F1/13363, i.e. to birefringent elements, e.g. for optical compensation, characterised by the number, position, orientation or value of the compensation plates with refractive index ellipsoid inclined, or tilted, relative to the LC-layer surface O plate
    • G02F2413/105—Indexing scheme related to G02F1/13363, i.e. to birefringent elements, e.g. for optical compensation, characterised by the number, position, orientation or value of the compensation plates with refractive index ellipsoid inclined, or tilted, relative to the LC-layer surface O plate with varying inclination in thickness direction, e.g. hybrid oriented discotic LC

Definitions

  • German Patent Publication No. 4,010,503A1 which is the closest prior art to the subject-matter of claim 1 discloses a negative uniaxial optical compensator for liquid crystal displays comprising a liquid crystalline polymer material comprising discotic groups, which are substantially horizontally aligned and fixed in this orientation.
  • an optical compensatory sheet is used to improve the liquid crystal display of a vertical alignment mode or a bend alignment mode in the same manner as in the conventional liquid crystal displays.
  • the known optical compensatory sheets used in the conventional liquid crystal displays are not effective in the liquid crystal display of the vertical alignment mode or the bend alignment mode.
  • optical compensatory sheet comprising an optically anisotropic layer containing discotic liquid crystal molecules has been proposed to be used in place of the stretched birefringent film.
  • the optically anisotropic layer of the known optical compensatory sheet does not have a large negative optical anisotropy in which an optical axis is not inclined.
  • the present inventors have tried to prepare an optical compensatory sheet having the required specific large negative optical anisotropy by using discotic liquid crystal molecules.
  • the present invention provides an optical compensatory sheet comprising an optically anisotropic layer formed of discotic liquid crystal molecules provided on a transparent substrate, wherein the discotic liquid crystal molecules are horizontally aligned in the optically anisotropic layer, an average inclined angle between discotic planes of said discotic liquid crystal molecules and a surface of said transparent substrate being less than 5°, and said discotic liquid crystal molecules being fixed in the optically anisotropic layer while keeping the horizontal alignment.
  • the invention also provides a liquid crystal display comprising a liquid crystal cell of a vertical alignment mode, two polarizing elements and one or two optical compensatory sheets, each of said polarizing elements being arranged on each side of the liquid crystal cell, each of said optical compensatory sheets being arranged between the liquid crystal cell and each polarizing element, wherein the optical compensatory sheet comprises an optically anisotropic layer formed of discotic liquid crystal molecules provided on a transparent substrate, said discotic liquid crystal molecules being horizontally aligned in the optically anisotropic layer, and wherein an average inclined angle between discotic planes of the discotic liquid crystal molecules and a surface of the transparent substrate is less than 5°, said discotic liquid crystal molecules being fixed in the optically anisotropic layer while keeping the horizontal alignment.
  • the present inventors have found that an optical compensatory sheet having a large negative optical anisotropy in which an optical axis is essentially not inclined can be obtained by adjusting an average inclined angle between discotic planes of discotic liquid crystal molecules and a surface of the transparent substrate to be less than 5°.
  • an optical compensatory sheet having a large negative optical anisotropy in which an optical axis is essentially not inclined can be obtained by adjusting an average inclined angle between discotic planes of discotic liquid crystal molecules and a surface of the transparent substrate to be less than 5°.
  • the present inventors have further studied the alignment of the discotic liquid crystal molecules, and have finally succeeded in aligning the discotic liquid crystal molecules having an average inclined angle of less than 5°.
  • the homeotropic alignment of the discotic liquid crystal molecule is obtained by using a specific amount (based on the discotic liquid crystal molecule) of a 1,3,5-triazine compound.
  • the optical compensatory sheet of the present invention has a large negative optical anisotropy in which an optical axis is essentially not inclined.
  • the optical compensatory sheet of the invention is particularly effective in a liquid crystal display of a vertical alignment mode or a bend alignment mode, in which most of rod-like liquid crystal molecules are essentially vertically aligned.
  • Fig. 2 is a sectional view schematically illustrating alignment of rod-like liquid crystal molecules in a liquid crystal cell of a bend alignment mode and discotic liquid crystal molecules in an optically anisotropic layer and a second optically anisotropic layer when voltage is not applied (off) or is applied (on) to the cell.
  • a liquid crystal display is described by referring to the drawings.
  • Fig. 1 is a sectional view schematically illustrating alignment of rod-like liquid crystal molecules in a liquid crystal cell of a vertical alignment mode and discotic liquid crystal molecules in an optically anisotropic layer when voltage is not applied (off) or is applied (on) to the cell.
  • a liquid crystal cell (11 to 13) comprises an upper substrate (11), a lower substrate (13) and liquid crystal (12) comprising rod-like liquid crystal molecules (12a to 12d) sealed between the substrates.
  • Each of the upper substrate (11) and the lower substrate (13) has an orientation layer and en electrode (not shown in Fig. 1).
  • the orientation layer has a function of aligning the rod-like liquid crystal molecules (12a to 12d).
  • the electrode has a function of applying voltage to the rod-like liquid crystal molecules (12a to 12d).
  • the rod-like liquid crystal molecules (12a to 12d) When voltage is not applied to the liquid crystal cell of a vertical alignment mode, the rod-like liquid crystal molecules (12a to 12d) are essentially vertically aligned as is shown in (off) of Fig. 1.
  • the rod-like liquid crystal molecules (12a to 12d) are slightly slanted (pretilted) to a direction (rightward in Fig. 1).
  • the slanted molecules can be aligned to the pretilted direction when voltage is applied to the cell, as is shown in (on) of Fig. 2.
  • An optical compensatory sheet (14 to 16) is provided under the liquid crystal cell (11 to 13).
  • the optical compensatory sheet shown in Fig. 1 comprises a transparent substrate (16), an orientation layer (15) and an optically anisotropic layer (14) in this order.
  • the optically anisotropic layer (14) is formed by aligning discotic liquid crystal molecules (14a) and fixing the molecules while keeping the alignment.
  • the rod-like liquid crystal molecules (12b, 12c) placed in the middle of the cell are essentially horizontally aligned.
  • the rod-like liquid crystal molecules (12a, 12d) neighboring the substrates (11, 13) are obliquely aligned along the pretilted direction.
  • Fig. 2 is a sectional view schematically illustrating alignment of rod-like liquid crystal molecules in a liquid crystal cell of a bend alignment mode and discotic liquid crystal molecules in an optically anisotropic layer and a second optically anisotropic layer when voltage is not applied (off) or is applied (on) to the cell.
  • a liquid crystal cell (21 to 23) comprises an upper substrate (21), a lower substrate (23) and liquid crystal (22) comprising rod-like liquid crystal molecules (22a to 22d) sealed between the substrates.
  • Each of the upper substrate (21) and the lower substrate (23) has an orientation layer and en electrode (not shown in Fig. 2).
  • the orientation layer has a function of aligning the rod-like liquid crystal molecules (22a to 22d).
  • the electrode has a function of applying voltage to the rod-like liquid crystal molecules (22a to 22d).
  • the alignment of the rod-like liquid crystal molecules (22a, 22b) near the upper substrate (21) is essentially antiparallel (symmetrical) to the alignment of the molecules (22c, 22d) near the lower substrate (23), as is shown in (off) of Fig. 2.
  • the rod-like liquid crystal molecules (22a, 22d) neighboring the substrates (21, 23) are essentially horizontally aligned.
  • the rod-like liquid crystal molecules (22b, 22c) placed in the middle of the cell are obliquely aligned.
  • an average inclined angle between discotic planes of the discotic liquid crystal molecules (25a to 25c) and a surface of the transparent substrate (27) is not less than 5°.
  • the inclined angle increases or decreases with increase of a distance from the surface of the transparent substrate to the discotic plane of the discotic liquid crystal molecules.
  • the inclined angle ( ⁇ a to ⁇ c) increases with increase of a distance from the surface of the transparent substrate (27) to the discotic plane of the discotic liquid crystal molecules (25a to 25c).
  • the alignment of the rod-like liquid crystal molecules (22a to 22d) is rather weak compared before applying voltage (off), as is shown in (on) of Fig. 2.
  • the alignment of the rod-like liquid crystal molecules (22a, 22b) near the upper substrate (21) is still essentially antiparallel (symmetrical) to the alignment of the molecules (22c, 22d) near the lower substrate (23).
  • the rod-like liquid crystal molecules (22a, 22d) neighboring the substrates (21, 23) are essentially horizontally aligned.
  • the rod-like liquid crystal molecules (22b, 22c) placed in the middle of the cell are obliquely aligned.
  • the term "essentially vertically (or horizontally)” and the term “essentially parallel (or perpendicular)” mean that a margin for error based on the exactly vertical, horizontal, parallel or perpendicular angle is in the range of ⁇ 20°.
  • the margin for error is preferably in the range of ⁇ 15°, more preferably in the range of ⁇ 10°, and most preferably in the range of ⁇ 5°.
  • the optically anisotropic layer is formed by aligning discotic liquid crystal molecules and fixing the molecules while keeping the alignment.
  • the discotic liquid crystal molecules are preferably fixed by a polymerization reaction, though the molecules can be fixed with a binder.
  • the discotic liquid crystal molecule is described in various documents (C. Destrade et al., Mol. Crysr. Liq. Cryst., vol. 71, page 111 (1981); Japan Chemical Society, Quarterly Chemical Review (written in Japanese), chapter 5 and chapter 10, section 2 (1994); B. Kohne et al., Angew. Chem. Soc. Chem. Comm., page 1794 (1985); and J. Zhang et al., J. Am. Chem. Soc., vol. 116, page 2655 (1994)).
  • the polymerization reaction of the discotic liquid crystal molecule is described in Japanese Patent Provisional Publication No. 8(1996)-27284.
  • LP means the combination of the divalent linking group (L) and the polymerizable group (P).
  • the divalent linking group (L) preferably is selected from the group consisting of an alkylene group, an alkenylene group, an arylene group, -CO, -NH-, -O-, -S- and combinations thereof.
  • L more preferably is a divalent linking group comprising at least two divalent groups selected from the group consisting of an alkylene group, an arylene group, -CO-, -NH-, -O- and -S-.
  • the alkylene group preferably has 1 to 12 carbon atoms.
  • the alkenylene group preferably has 2 to 12 carbon atoms.
  • the arylene group preferably has 6 to 10 carbon atoms.
  • the polymerizable group (P) is determined by the polymerization reaction. Examples of the polymerizable groups (P) are shown below.
  • n is an integer of 4 to 12, which is determined by the chemical structure of the discotic core (D).
  • the 4 to 12 combinations of L and P can be different from each other. However, the combinations are preferably identical.
  • the 1,3,5-triazine compound is preferably represented by the following formula (III). in which each of X 1 , X 2 and X 3 independently is a single bond, -NR- (wherein R is hydrogen or an alkyl group having 1 to 30 carbon atoms), -O- or -S-; and each of R 31 , R 32 and R 33 independently is an alkyl group, an alkenyl group, an aryl group or a heterocyclic group.
  • the compound represented by the formula (III) preferably is a melamine compound.
  • the melamine compound means that each of X 1 , X 2 and X 3 is -NR- or that each of X 1 , X 2 and X 3 is a single bond and each of R 31 , R 32 and R 33 independently is a heterocyclic group having a free valence at nitrogen atom.
  • the melamine compound is described below by referring to the formula (IV).
  • R of -NR- preferably is hydrogen.
  • Each of R 31 , R 32 and R 33 preferably is an aryl group.
  • the alkenyl group preferably has a chain structure rather than a cyclic structure.
  • An alkenyl group of a straight chain structure is preferred to an alkenyl group of a branched chain structure.
  • the alkenyl group preferably has 2 to 30 carbon atom, more preferably has 3 to 30 carbon atoms, further preferably has 4 to 30 carbon atoms, and most preferably has 6 to 30 carbon atoms.
  • the alkenyl group may have a substituent group. Examples of the substituent groups include a halogen atom, an alkoxy group (e.g., methoxy, ethoxy, epoxyethyloxy) and an acyloxy group (e.g., acryloyloxy, methacryloyloxy).
  • the alkyl group has the same meanings as is described' above.
  • the alkyl moieties of the alkoxy group, the acyloxy group, the alkoxycarbonyl group, the alkyl substituted sulfamoyl group, the sulfonamido group, the alkyl substituted carbamoyl group, the amido group, the alkylthio group and the acyl group also have the same meanings as is described above.
  • aryl groups include phenyl, a-naphthyl, b-naphthyl, 4-methoxyphenyl, 3,4-diethoxyphenyl, 4-octyloxyphenyl and 4-dodecyloxyphenyl.
  • phenyl moieties of the aryloxy group, the acyloxy group, the aryloxycarbonyl group, the aryl substituted sulfamoyl group, the sulfonamido group, the aryl substituted carbamoyl group, the amido group, the arylthio group and the acyl group are the same as the examples of the phenyl group.
  • the heterocyclic group preferably has aromaticity.
  • An aromatic heterocyclic ring generally is an unsaturated heterocyclic ring, and preferably is a heterocyclic ring having the maximum number of double bonds.
  • the heterocyclic ring preferably is a five-membered, six-membered or seven-membered ring, more preferably is a five-membered or six-membered ring, and most preferably is a six-membered ring.
  • the hetero atom of the ring preferably is N, S or O, and more preferably is N.
  • the aromatic heterocyclic ring most preferably is pyridine ring.
  • the heterocyclic group preferably is 2-pyridyl or 4-pyridyl.
  • the heterocyclic group may have a substituent group. Examples of the substituent groups are the same as those of the substituent groups of the aryl group.
  • the heterocyclic group preferably has a free valence at nitrogen atom.
  • the heterocyclic ring preferably is a five-membered, six-membered or seven-membered ring, more preferably is a five-membered or six-membered ring, and most preferably is a five-membered ring.
  • the heterocyclic ring may contain two or more nitrogen atoms.
  • the heterocyclic ring may contain another hetero atom (e.g., O, S).
  • the heterocyclic ring may have a substituent group. Examples of the substituent groups are the same as those of the substituent groups of the aryl group. Examples of the heterocyclic groups having a free valence at nitrogen atom are shown below.
  • At least one of R 31 , R 32 and R 33 preferably contains an alkylene moiety having 9 to 30 carbon atoms or an alkenylene moiety having 9 to 30 carbon atoms.
  • the alkylene moiety or the alkenylene moiety preferably has a straight chain structure.
  • the alkylene moiety or the alkenylene moiety is preferably contained in a substituent group of an aryl group.
  • At least one of R 31 , R 32 and R 33 preferably contains a polymerizable group as a substituent group.
  • the 1,3,5-triazine compound preferably has at least two polymerizable groups.
  • the polymerizable group is preferably positioned at the end of R 31 , R 32 or R 33 .
  • the discotic liquid crystal molecules and the 1,3,5-triazine compound can be polymerized in the optical anisotropic layer.
  • R 31 , R 32 or R 33 having a polymerizable group as a substituent group are represented by the formula (Rp). (Rp) -L 5 (-P)n in which L 5 is a (n+1) valent linking group; P is a polymerizable group; and n is an integer of 1 to 5.
  • L 5 preferably is a linking group consisting of at least two of an alkylene group, an alkenylene group, a (n+1) valent aromatic group, a divalent heterocyclic group, -CO-, -NR- (wherein R is hydrogen or an alkyl group having 1 to 30 carbon atoms), -O-, -S- and -SO 2 -.
  • the alkylene group preferably has 1 to 12 carbon atoms.
  • the alkenylene group preferably has 2 to 12 carbon atoms.
  • the aromatic group preferably has 6 to 10 carbon atoms.
  • L 5 of the formula (Rp) examples are shown below.
  • the left side is attached to X 1 , X 2 or X 3 (or directly attached to 1,3,5-triazine ring where X 1 , X 2 or X 3 is a single bond) in the formula (III).
  • the right side is attached to a polymerizable group (P).
  • AL means an alkylene group or alkenylene group
  • Hc means a divalent heterocyclic group
  • AR means an aromatic group.
  • the alkylene group, the alkenylene group, the heterocyclic group and the aromatic group may have a substituent group (e.g., an alkyl group, a halogen atom).
  • the 1,3,5-triazine compound preferably is a melamine compound represented by the formula (IV). in which each of R 41 , R 43 and R 45 independently is hydrogen or an alkyl group having 1 to 30 carbon atoms; and each of R 42 , R 44 and R 46 independently is an alkyl group, an alkenyl group, an aryl group or a heterocyclic group; or R 41 and R 42 , R 43 and R 44 or R 45 and R 46 are combined to form a heterocyclic ring.
  • each of R 41 , R 43 and R 45 independently is hydrogen or an alkyl group having 1 to 30 carbon atoms
  • each of R 42 , R 44 and R 46 independently is an alkyl group, an alkenyl group, an aryl group or a heterocyclic group
  • R 41 and R 42 , R 43 and R 44 or R 45 and R 46 are combined to form a heterocyclic ring.
  • Each of R 41 , R 43 and R 45 preferably is hydrogen or an alkyl group having 1 to 20 carbon atoms, more preferably is hydrogen or an alkyl group having 1 to 10 carbon atoms, further preferably is hydrogen or an alkyl group having 1 to 6 carbon atoms, and most preferably is hydrogen.
  • Each of R 42 , R 44 and R 46 preferably is an aryl group.
  • the heterocyclic ring formed by R 41 and R 42 , R 43 and R 44 or R 45 and R 46 is the same as the heterocyclic group having a free valence at nitrogen atom described in the formula (III).
  • At least one of R 42 , R 44 and R 46 preferably contains an alkylene moiety having 9 to 30 carbon atoms or an alkenylene moiety having 9 to 30 carbon atoms.
  • the alkylene moiety or the alkenylene moiety preferably has a straight chain structure.
  • the alkylene moiety or the alkenylene moiety is preferably contained in a substituent group of an aryl group.
  • At least one of R 42 , R 43 and R 44 preferably contains a polymerizable group as a substituent group.
  • the melamine compound preferably has at least two polymerizable groups.
  • the polymerizable group is preferably positioned at the end of R 42 , R 44 or R 46 .
  • the discotic liquid crystal molecules and the melamine compound can be polymerized in the optical anisotropic layer.
  • R 42 , R 44 or R 46 having a polymerizable group as a substituent group are the same as the groups represented by the formula (Rp).
  • a melamine polymer can be used as the melamine compound.
  • the melamine polymer is preferably synthesized from a melamine compound and a carbonyl compound by a reaction represented by the formula (V). in which each of R 71 , R 72 , R 73 , R 74 , R 75 and R 76 independently is hydrogen, an alkyl group, an alkenyl group, an aryl group or a heterocyclic group.
  • the polymerization reaction of the melamine compound and the carbonyl compound is the same as the synthesizing reaction of a conventional melamine resin (e.g., melamine formaldehyde resin).
  • a conventional melamine resin e.g., melamine formaldehyde resin
  • a commercially available melamine polymer (melamine resin) can be used in the present invention.
  • the melamine polymer has a molecular weight preferably in the range of 2,000 to 400,000.
  • An optical compensatory sheet was prepared in the same manner as in Reference Example 2, except that cellulose acetate butyrate (CAB-321-0.1) was not used.
  • An aqueous solution of an alkyl denatured polyvinyl alcohol (MP-203, Kuraray Co., Ltd.) was coated on the transparent substrate by using a bar coater, and dried to form an orientation layer (thickness: 0.65 ⁇ m). The surface of the orientation layer was subjected to a rubbing treatment.
  • the following coating solution was coated on the orientation layer by using a wire bar coater, and dried at the room temperature. The thickness of the formed layer was 1.7 ⁇ m.
  • Coating solution for optically anisotropic layer Fluorine containing surface active agent (FS-3) 3 weight parts The discotic liquid crystal compound (1) used in Example 1 100 weight parts A photopolymerization initiator (Irgacure 907, Ciba-Geigy) 0.2 weight part Methyl ethyl ketone 400 weight parts
  • the coated layer was heated at 115°C to align the discotic liquid crystal compound.
  • the layer was irradiated with an ultraviolet ray of 600 mJ per cm 2 to polymerize the liquid crystal compound and to fix the alignment.
  • an optical compensatory sheet was prepared.
  • a glass plate (thickness: 0.85 mm) was used as a transparent substrate.
  • An aqueous solution of polyvinyl alcohol denatured with methacryloyloxyethyl isocyanate (Polymer No. 1 of Japanese Patent Provisional Publication No. 8(1996)-48197) was coated on the transparent substrate by using a bar coater, and dried to form an orientation layer (thickness: 0.63 ⁇ m). The surface of the orientation layer was subjected to a rubbing treatment.
  • the coated layer was heated at 180°C to align the discotic liquid crystal compound.
  • the layer was irradiated with an ultraviolet ray of 600 mJ per cm 2 to polymerize the liquid crystal compound and to fix the alignment.
  • an optical compensatory sheet was prepared.
  • Optical compensatory sheets were prepared in the same manner as in Reference Example 20, except that the kind of the discotic liquid crystal compound, the kind or amount of the fluorine containing surface active agent or the heating temperature for the layer was changed as is shown in Table 3.
  • a triacetyl cellulose film (thickness: 100 ⁇ m, size: 270 mm ⁇ 100 mm, Fuji Tac, Fuji Photo Film Co., Ltd.) was used as a transparent substrate.
  • the coating solution used in Reference Example 1 was coated on the orientation layer by using a wire bar coater.
  • the coated layer was heated at 106°C to align the discotic liquid crystal compound.
  • the layer was irradiated with an ultraviolet ray of 2 J to polymerize the liquid crystal compound and to fix the alignment.
  • an optical compensatory sheet was prepared.
  • a triacetyl cellulose film (thickness: 100 ⁇ m, size: 270 mm ⁇ 100 mm, Fuji Tac, Fuji Photo Film Co., Ltd.) was used as a transparent substrate.
  • the coating solution used in Reference Example 1 was coated on the transparent substrate by using a wire bar coater.
  • the coated layer was heated at 106°C to align the discotic liquid crystal compound.
  • the layer was irradiated with an ultraviolet ray of 2 J to polymerize the liquid crystal compound and to fix the alignment.
  • an optical compensatory sheet was prepared.
  • An aqueous solution of an alkyl denatured polyvinyl alcohol (MP-203, Kuraray Co., Ltd.) was coated on the transparent substrate by using a bar coater, and dried (without conducting a rubbing treatment) to form an orientation layer (thickness: 0.65 ⁇ m).
  • the coating solution used in Reference Example 8 was coated on the orientation layer by using a wire bar coater, and dried at the room temperature.
  • the thickness of the formed layer was 1.7 ⁇ m.
  • the coated layer was heated at 115°C to align the discotic liquid crystal compound.
  • the layer was irradiated with an ultraviolet ray of 600 mJ per cm 2 to polymerize the liquid crystal compound and to fix the alignment.
  • an optical compensatory sheet was prepared.
  • the coating solution used in Reference Example 8 was coated on the transparent substrate by using a wire bar coater, and dried at the room temperature.
  • the thickness of the formed layer was 1.7 ⁇ m.
  • the coated layer was heated at 115°C to align the discotic liquid crystal compound.
  • the layer was irradiated with an ultraviolet ray of 600 mJ per cm 2 to polymerize the liquid crystal compound and to fix the alignment.
  • an optical compensatory sheet was prepared.
  • a glass plate (thickness: 0.85 mm) was used as a transparent substrate.
  • An aqueous solution of polyvinyl alcohol denatured with methacryloyloxyethyl isocyanate (Polymer No. 1 of Japanese Patent Provisional Publication No. 8(1996)-48197) was coated on the transparent substrate by using a bar coater, and dried (without conducting a rubbing treatment) to form an orientation layer (thickness: 0.63 ⁇ m).
  • the coating solution used in Reference Example 20 was coated on the orientation layer by using a spin coater of 1,000 rpm, and dried at the room temperature.
  • the thickness of the formed layer was 1.9 ⁇ m.
  • the coated layer was heated at 180°C to align the discotic liquid crystal compound.
  • the layer was irradiated with an ultraviolet ray of 600 mJ per cm 2 to polymerize the liquid crystal compound and to fix the alignment.
  • an optical compensatory sheet was prepared.
  • the coating solution used in Reference Example 20 was coated on the transparent substrate by using a spin coater of 1,000 rpm, and dried at the room temperature.
  • the thickness of the formed layer was 1.9 ⁇ m.
  • the coated layer was heated at 180°C to align the discotic liquid crystal compound.
  • the layer was irradiated with an ultraviolet ray of 600 mJ per cm 2 to polymerize the liquid crystal compound and to fix the alignment.
  • an optical compensatory sheet was prepared.
  • a glass plate (thickness: 0.85 mm) was used as a transparent substrate.
  • An aqueous solution of polyvinyl alcohol denatured with methacryloyloxyethyl isocyanate (Polymer No. 1 of Japanese Patent Provisional Publication No. 8(1996)-48197) was coated on the transparent substrate by using a bar coater, and dried (without conducting a rubbing treatment) to form an orientation layer (thickness: 0.54 ⁇ m). The surface of the orientation layer was subjected to a rubbing treatment.
  • the following coating solution was coated on the orientation layer by using a spin coater of 1,000 rpm, and dried at the room temperature.
  • the thickness of the formed layer was 1.34 ⁇ m
  • Coating solution for (second) optically anisotropic layer The discotic liquid crystal compound (1) used in Reference Example 1 100 weight parts A photopolymerization initiator (Irgacure 907, Ciba-Geigy) 0.2 weight part Methyl ethyl ketone 400 weight parts
  • the coated layer was heated at 135°C to align the discotic liquid crystal compound.
  • the layer was irradiated with an ultraviolet ray of 600 mJ per cm 2 to polymerize the liquid crystal compound and to fix the alignment.
  • an optical compensatory sheet was prepared.
  • a second optically anisotropic layer was formed in the same manner as in Comparison Example 19.
  • the following coating solution was coated on the second optically anisotropic layer by using a bar coater, and dried at the room temperature.
  • Coating solution for (first) optically anisotropic layer Cellulose acetate butyrate (acetic acid content: 3.0%, butyric acid content: 50.0%, CAB-531-1, Eastman Chemical) 0.3 weight part
  • the discotic liquid crystal compound (1) used in Example 1 100 weight parts
  • the coated layer was heated at 106°C to align the discotic liquid crystal compound.
  • the layer was irradiated with an ultraviolet ray of 2 J per cm 2 to polymerize the liquid crystal compound and to fix the alignment.
  • an optical compensatory sheet was prepared.
  • Two optical compensatory sheets prepared in Comparison Example 19 or Reference Example 38 were attached to each side of a liquid crystal cell of a bend alignment mode.
  • the product of the difference in refractive index (between ordinary ray and extraordinary ray) and the gap size of the cell was 350 nm.
  • a voltage (0 to 5 V) of a square wave (40 Hz) was applied to the liquid crystal cell, and the angle dependency of the transmittance (T) was measured.
  • a triacetyl cellulose film (thickness: 100 ⁇ m, size: 270 mm ⁇ 100 mm, Fuji Tac, Fuji Photo Film Co., Ltd.) was used as a transparent substrate.
  • Coating solution for optically anisotropic layer Melamine compound (MM-2) 0.5 weight part
  • the discotic liquid crystal compound (1) used in Reference Example 1 100 weight parts
  • the coated layer was heated at 120°C to align the discotic liquid crystal compound.
  • the layer was irradiated with an ultraviolet ray of 600 mJ per cm 2 to polymerize the liquid crystal compound and to fix the alignment.
  • an optical compensatory sheet was prepared.
  • Optical compensatory sheets were prepared in the same manner as in Example 39, except that the kind or amount of the melamine compound was changed as is shown in Table 5.
  • Example 44 MM-1 5 parts 1.3° -121 nm
  • Example 45 MM-3 5 parts 2.0° -129 nm
  • Example 46 MM-5 5 parts 1.1° -130 nm
  • Example 47 MM-17 5 parts 3.0° -124 nm
  • Example 48 MM-19 5 parts 1.9° -128 nm
  • Example 49 MM-26 5 parts 0.5° -130 nm
  • Example 50 MM-50 5 parts 2.1° -111 nm
  • Example 51 MM-54 5 parts 1.2° -119 nm
  • Example 52 MM-62 5 parts 2.4° -125 nm
  • Example 53 MM-89 5 parts 0.8° -123 nm
  • Example 54 MM-96 5 parts 1.9° -119 nm
  • Example 55 MM-27 5 parts 1.3° -121 nm
  • Example 56 MM-31 5 parts 0.9° -118 nm
  • Example 57 MM-33 5 parts 1.5° -123
  • a glass plate (thickness: 0.85 mm) was used as a transparent substrate.
  • An aqueous solution of polyvinyl alcohol denatured with methacryloyloxyethyl isocyanate (Polymer No. 1 of Japanese Patent Provisional Publication No. 8(1996)-48197) was coated on the transparent substrate by using a bar coater, and dried to form an orientation layer (thickness: 0.63 ⁇ m). The surface of the orientation layer was subjected to a rubbing treatment.
  • Coating solution for optically anisotropic layer Melamine compound (MM-2) 0.5 weight part
  • the discotic liquid crystal compound (5) used in Reference Example 20 100 weight parts
  • the coated layer was heated at 180°C to align the discotic liquid crystal compound.
  • the layer was irradiated with an ultraviolet ray of 600 mJ per cm 2 to polymerize the liquid crystal compound and to fix the alignment.
  • an optical compensatory sheet was prepared.
  • Optical compensatory sheets were prepared in the same manner as in Example 60, except that the kind of the discotic liquid crystal compound, the kind or amount of the melamine compound or the heating temperature for the layer was changed as is shown in Table 6.
  • An alkyl denatured polyvinyl alcohol (MP-203, Kuraray Co., Ltd.) was coated on the transparent substrate, and dried to form an orientation layer.
  • Coating solution Melamine polymer (MP-5) 1 weight part
  • the discotic liquid crystal compound (1) used in Example 1 100 weight parts Methyl ethyl ketone 400 weight parts
  • the coated sample was gradually heated, and the change of the liquid crystal phase was observed with a polarizing microscope. As a result, a liquid crystal phase was observed in the range of 116 to 180°C.
  • An aqueous solution of an alkyl denatured polyvinyl alcohol (MP-203, Kuraray Co., Ltd.) was coated on the transparent substrate, and dried to form an orientation layer.
  • Coating solution for optically anisotropic layer Melamine polymer (MP-5) 1 weight part
  • the discotic liquid crystal compound (1) used in Reference Example 1 100 weight parts
  • the coated layer was heated at 130°C to align the discotic liquid crystal compound.
  • the layer was irradiated with an ultraviolet ray of 600 mJ per cm 2 to polymerize the liquid crystal compound and to fix the alignment.
  • an optical compensatory sheet was prepared.
  • the alignment of the optically anisotropic layer was kept after polymerizing the discotic liquid crystal compound and cooling the layer. After heating the layer at 130°C, the optically anisotropic layer was not changed to the liquid crystal state.
  • the inclined angle of the optic axis was measured by using an ellipsometer (AEP-100, Shimazu Seisakusho, Ltd.). As a result, the angle was less than 5°.
  • An optical compensatory sheet was prepared in the same manner as in Example 86, except that 1 weight part of the following melamine polymer (MP-7) was used in place of the melamine polymer (MP-5).
  • the alignment of the optically anisotropic layer was kept after polymerizing the discotic liquid crystal compound and cooling the layer. After heating the layer at 130°C, the optically anisotropic layer was not changed to the liquid crystal state.
  • the inclined angle of the optic axis was measured by using an ellipsometer (AEP-100, Shimazu Seisakusho, Ltd.). As a result, the angle was less than 5°.

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Claims (8)

  1. Optisches Kompensationsblatt (14-16), das eine optisch anisotrope Schicht (14) umfaßt, die von diskotischen Flüssigkristallmolekülen (14a) gebildet wird, die auf einem transparenten Substrat (16) vorgesehen sind, wobei die diskotischen Flüssigkristallmoleküle in der optisch anisotropen Schicht horizontal ausgerichtet sind, ein mittlerer Neigungswinkel zwischen diskotischen Ebenen der diskotischen Flüssigkristallmoleküle und einer Oberfläche des transparenten Substrats weniger als 5° beträgt und die diskotischen Flüssigkristallmoleküle in der optisch anisotropen Schicht fixiert sind, wobei die horizontale Ausrichtung beibehalten wird, dadurch gekennzeichnet, daß die optisch anisotrope Schicht weiterhin eine 1,3,5-Triazinverbindung in einer Menge von 0,01 bis 20 Gew.%, bezogen auf die Menge der diskotischen Flüssigkristallmoleküle, enthält.
  2. Optisches Kompensationsblatt (14-16) gemäß Anspruch 1, worin die diskotischen Flüssigkristallmoleküle (14a) polymerisiert sind.
  3. Optisches Kompensationsblatt (14-16) gemäß Anspruch 1, worin die 1,3,5-Triazinverbindung eine Melaminverbindung ist.
  4. Optisches Kompensationsblatt (14-16) gemäß Anspruch 3, worin die 1,3,5-Triazinverbindung ein Melaminpolymer ist.
  5. Optisches Kompensationsblatt (14-16) gemäß Anspruch 2, worin die diskotischen Flüssigkristallmoleküle (14a) und die 1,3,5-Triazinverbindung in der optisch anisotropen Schicht (14) polymerisiert sind.
  6. Optisches Kompensationsblatt (24-27) gemäß Anspruch 1, worin das optische Kompensationsblatt weiterhin eine zweite optisch anisotrope Schicht (25) umfaßt, die von diskotischen Flüssigkristallmolekülen (25a-25c) gebildet wird, die diskotischen Flüssigkristallmoleküle in der zweiten optisch anisotropen Schicht ausgerichtet sind und worin ein mittlerer Neigungswinkel zwischen diskotischen Ebenen der diskotischen Flüssigkristallmoleküle und einer Oberfläche des transparenten Substrats (27) nicht weniger als 5° beträgt und sich der Neigungswinkel mit steigendem Abstand von der Oberfläche des transparenten Substrats zu der diskotischen Ebene des diskotischen Flüssigkristallmoleküls vergrößert oder verkleinert.
  7. Flüssigkristallanzeige, die eine Flüssigkristallzelle vom vertikalen Ausrichtungsmodus ("vertical alignment mode") (11-13), zwei polarisierende Elemente und ein oder zwei optische Kompensationsblätter (14-16) umfaßt, worin jedes der polarisierenden Elemente auf jeder Seite der Flüssigkristallzelle angeordnet ist, jedes der optischen Kompensationsblätter zwischen der Flüssigkristallzelle und jedem polarisierenden Element angeordnet ist, wobei das optische Kompensationsblatt ein optisches Kompensationsblatt gemäß irgendeinem der Ansprüche 1 bis 5 ist.
  8. Flüssigkristallanzeige, die eine Flüssigkristallzelle vom gebogenen Ausrichtungsmodus ("bend alignment mode") (21-23), zwei polarisierende Elemente und ein oder zwei optische Kompensationsblätter (24-27) umfaßt, worin jedes der polarisierenden Elemente auf jeder Seite der Flüssigkristallzelle angeordnet ist, jedes der optischen Kompensationsblätter zwischen der Flüssigkristallzelle und jedem polarisierenden Element angeordnet ist, wobei das optische Kompensationsblatt ein optisches Kompensationsblatt gemäß irgendeinem der Ansprüche 1 bis 6 ist.
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KR100422196B1 (ko) 2004-03-12
KR19990067771A (ko) 1999-08-25
DE69925320T2 (de) 2006-02-02
EP0928984B8 (de) 2005-07-06
DE69925320D1 (de) 2005-06-23
EP0928984A2 (de) 1999-07-14
EP0928984A3 (de) 1999-07-28

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